Setter Injection with Map parameter in spring

Setter Injection with Map parameter in spring example.

In this example, we are using map as the answer for a question that have answer as the key and username as the value. Here, we are using key and value pair both as a string.

Like previous examples, it is the example of forum where one question can have multiple answers.

Question.java

This class contains three properties, getters & setters and displayInfo() method to display the information.

1. package com.tpyyes;  
2. import java.util.Iterator;  
3. import java.util.Map;  
4. import java.util.Set;  
5. import java.util.Map.Entry;  
6.   
7. public class Question {  
8. private int id;  
9. private String name;  
10. private Map<String,String> answers;  
11.   
12. //getters and setters  
13.   
14. public void displayInfo(){  
15.     System.out.println("question id:"+id);  
16.     System.out.println("question name:"+name);  
17.     System.out.println("Answers....");  
18.     Set<Entry<String, String>> set=answers.entrySet();  
19.     Iterator<Entry<String, String>> itr=set.iterator();  
20.     while(itr.hasNext()){  
21.         Entry<String,String> entry=itr.next();  
22.         System.out.println("Answer:"+entry.getKey()+" Posted By:"+entry.getValue());  
23.     }  
24. }  
25. }  

applicationContext.xml

The entry attribute of map is used to define the key and value information.

1. <?xml version="1.0" encoding="UTF-8"?>  
2. <beans  
3.     xmlns="http://www.springframework.org/schema/beans"  
4.     xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"  
5.     xmlns:p="http://www.springframework.org/schema/p"  
6.     xsi:schemaLocation="http://www.springframework.org/schema/beans   
7. http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">  
8.   
9. <bean id="que" class="com.tpyyes.Question">  
10. <property name="id" value="1"></property>  
11. <property name="name" value="What is Java?"></property>  
12. <property name="answers">  
13. <map>  
14. <entry key="Java is a programming language"  value="Sonoo Jaiswal"></entry>  
15. <entry key="Java is a Platform" value="Sachin Yadav"></entry>  
16. </map>  
17. </property>  
18. </bean>  
19.   
20. </beans>  

Test.java

This class gets the bean from the applicationContext.xml file and calls the displayInfo() method.

1. package com.tpyyes;  
2.   
3. import org.springframework.beans.factory.BeanFactory;  
4. import org.springframework.beans.factory.xml.XmlBeanFactory;  
5. import org.springframework.core.io.ClassPathResource;  
6. import org.springframework.core.io.Resource;  
7.   
8. public class Test {  
9. public static void main(String[] args) {  
10.     Resource res=new ClassPathResource("applicationContext.xml");  
11.     BeanFactory factory=new XmlBeanFactory(res);  
12.       
13.     Question q=(Question)factory.getBean("que");  
14.     q.displayInfo();  
15.       
16. }  
17. }